Physiologists at the University of California, Los Angeles, have created an interdepartmental Ph.D. program (IDP) in Molecular, Cellular, & Integrative Physiology (MCIP) that is designed to provide training for predoctoral students that will enable those students to meet new challenges in biomedical and life science research. In the view of the training faculty, there is an important and growing need for biomedical researchers who can design and perform cellular and molecular manipulations that can be interpreted in the complex, in vivo, physiological environment. Our goal is to help to meet that need. A great strength of our program is that it is founded upon the established abilities of the training faculty to perform state-of-the-art research in physiology that integrates molecular, cellular and systemic functions. Furthermore, the faculty has a long history of successful training of pre-doctoral and post-doctoral students who have continued in their own successful scientific careers. The program has been further strengthened by a curriculum in which integrative approaches to modern, physiological research are emphasized. The quality of the MCIP faculty, our program and the success of our students was reflected in the most recent ranking of Physiology doctorate programs in the United States by the National Research Council (NRC). According to the NRC, the MCIP program is the first (R-ranking) or second (S-ranking) most highly-ranked Physiology program in the United States. In this renewal application, continued funding is requested for 6 NRSA supported traineeships per year. This support will be provided to the most highly-qualified predoctoral students early in their graduate training, while they complete research rotations and graduate coursework in Molecular, Cellular, & Integrative Physiology, and begin the development of their thesis research. Trainees will be recruited nationally and be selected for the program if they have demonstrated high academic achievement, experience in research, and high promise for a successful future in research and teaching in biomedical or life sciences. We anticipate that the students who complete their Ph.D. training in our program will be well-equipped for careers of scientific discovery at interface between molecular biology and systemic function. Those new researchers can advance our knowledge of fundamental mechanisms of organismic function that can potentially provide a basis for the understanding and treatment of human diseases.